Water valve vacuum line

[TomoHawk]

In a 280Z, can you reach the to of the water valve to replace the vacuum hose without have to take the whole dashboard out? Maybe you can you just reach in where the heater core is?

[Captain Obvious]

Are you talking about the vacuum control lines (which only exist on the cars with air conditioning), or are you talking about the hard copper line that comes out of the top of the water control valve? (Or something else completely?)

[Zed Head]

Some of the 280Z's, maybe all of them, have a vacuum controlled water ****. Apparently, there's an on-off water **** (the vacuum controlled one) and there's a flow control water ****, the one with the copper tube that runs to the heater core.

Regardless, if you stick your head up under the passenger side dash you can see both. Removing the glove box might be the easiest way to see and work with them, without removing the dash, if you don't want to do the yoga.

[Captain Obvious]

Some of the 280Z's, maybe all of them, have a vacuum controlled water ****. Apparently, there's an on-off water **** (the vacuum controlled one) and there's a flow control water ****, the one with the copper tube that runs to the heater core

The vacuum control lines only exist on the cars with A/C. The non-A/C cars are completely cable actuated mechanical only. That's why I asked if the car had A/C or not. I'm not sure what lines he's talking about here. I'm not sure if he's talking about the vacuum control line to the ON-OFF A/C derived water ****, or is he mistaking the hard copper line to the temp control valve for a vacuum line?

In any event, I'll jump to the end of the chase here and say that I've recently messed with my system, and it all depends on how small your hands are and how long you can work while laying on your back with your head up under the dash. I don't think there's any vacuum line that you cannot get to if your hands are small enough and you are flexible enough to deal with the contortions. However, I've decided that if I ever have to do major work to the heater system again, it would be easier to just pull the dash. It's just not that hard to pull it, and working on anything heater related after that is just so easy that it's not worth it (for me at least) to try to do anything significant with the dash in place.

Here's my bottom line... If you've got one tube that is leaking and you want to address just that one, then maybe preform the contortions. But my guess is that if there's one that needs to be replaced, then there are probably several others that should be as well.

[TomoHawk]

There was never any air-conditioning stuff in the car ever since I had it. but it's the vacuum line. I squeezed it, and the sucking noise stopped. I traced it up as far as I could reach, but I will remove the glovebox to see what else I can see.

Do you even need that one? I only hear the noise when I use the heater or defroster.

thxZ

Edited September 18, 2012 by TomoHawk

[TomoHawk]

I looked into this, and after removing the glovebox, there is nothing you can get to, except the defroster nozzle & hose. This vacuum hose is not reachable, and so is beyond my abilities.

[Zed Head]

Sorry for the bad information. It must be farther up behind the fan motor than I remember. I know that if you lay on your back on the passenger side floor and jam yourself up in there that you can see everything. Hoses entering the cabin, water and vacuum cocks, etc. I've had luck looking around corners with a mirror and a flashlight, if you want to try to get a peek before you commit to getting stuck.

If you squeezed the hose from the engine bay, maybe it can be reached through the hole from the engine bay. Just a thought, the nipple might be right there on the other side.

Edited September 19, 2012 by Zed Head

[Captain Obvious]

Here's a pic of the water control valves. The spring loaded over-engineered device on the right is controlled by the temp slider, and the flying saucer shaped diaphragm actuator on the left shuts off all the water when you turn the A/C on regardless of where the temp slider is positioned.

I'm no expert on the HVAC system, but I'm still thinking that maybe you shouldn't have any vacuum stuff in there at all unless the car has A/C. Maybe your car had A/C at one time, but a previous owner removed some (but not all) of it? You've got the vacuum switching valves in the engine compartment

Is the hose going to the diaphragm the one having troubles with?

[TomoHawk]

Since I can't see up there or get up there with my hand, I can't can give you an answer to that. Sorry, but thanks for the picture anyway.

[Captain Obvious]

Sorry I couldn't be of more help. So if you do end up pulling the dash...

What year are you working with? I just pulled dashes out of both a 74 and a 77, and the 77 was easier. The 74 required disconnection of a bunch of electrical connectors at the steering column, and by the time 77 rolled along Datsun had gotten a little smarter and rerouted all those connections to the firewall. The only electrical connections you have to mess with in 77 are three large connectors all located at the junction box above the passengers right knee.

Leave all the HVAC stuff in place. You don't have to mess with any of it to pull the dash. In fact, you can even leave the faceplate with the map light and fuel warning light in place. Leave the glove box in place as well. Don't forget to disconnect and reconnect the speedo cable.

What else...?

If your clock doesn't work, it's a lot easier to remove with the dash out of the car.

If you find an evaporator core in the top of your HVAC system, then you used to have A/C.

[TomoHawk]

There was no need to remove the entire dash panel. I took out the glovebox, centre console, etc., and the HVAC tech guy was able to install all new rubber vacuum lines in an hour. He says the vacuum sound was from a leak in the main hose to the intake.

So I reinstalled everything today, and I now have full control over the heater functions. Now I can drive around until November, in comfort and have a clear windscreen (after a brief warm-up.)

Edited September 21, 2012 by TomoHawk

[Captain Obvious]

the HVAC tech guy was able to install all new rubber vacuum lines in an hour.

Excellent. That's an even better solution! An HVAC guy with small hands. Another crisis averted!